Abstract [en]

This thesis the potential of using the heat from the chillers to meet the heating needs of an existing property was investigated. The property is owned and used by defense group Saab AB and has three different refrigeration plants serving different buildings. The work began with a survey of the cooling and heat demand to determine the magnitude of the overlap of these in the various buildings. Then one of the refrigeration plants was selected for deeper studies of how it could contribute to cover the heating demand. All three buildings have significant overlap between the cooling and heating requirements and thus great potential for saving energy by recovering the heat from the chillers.

The building internally designated building D has very good potential for heat recovery from the cooling systems and such is already installed.

Building A and building B both have large overlap between heating and cooling (about 1,900 and 1,400 MWh / year), but the design of the existing heating system causes some difficulties, using the heat from the chillers in practice.

Building A was chosen for further studies. Various solutions to recover the heat from the cooling systems were investigated. The most advantageous solution involves installing new heating ducts to heat the return water from preheaters of ventilation units. The measure includes changes in chiller operation by way of changed condensing temperature and slight adjustment of temperature levels in the ventilation units. Otherwise the action primarily consists of interconnecting heat consumers with chillers rather than any major changes to the heating system or chillers. Such a solution could recover nearly 1,400 MWh of heat per year and provide a net operating cost savings of more than 800,000 SEK per year. The payback period is estimated to be about 2 ½ years but the uncertainty in the investment costs to implement the proposed measure and thus the repayment period is very large.